Offset printing machines

ABSTRACT

Apparatus for mounting distributor and dampening rollers in an offset printing machine. The distributor roller is journaled in a bearing secured in fixed bushing and the dampening roller is mounted on an arm extending from a body surrounding the bushing. The body is provided with key means permitting adjustable rotative positioning about the bushing.

United States Patent Stepanek et al. [45] Apr. 18, 1972 [54] OFFSETPRINTING MACHINES [56] References Cited [72] Inventors: Karel Stepanek,Drnovice; Josef Zellnka, UNITED STATES PATENTS Bukovina, both ofCzechoslovakia 2 590 806 3/1952 v d 226/176 x i or erstrasse [731Ass'gnw mdni 3,561,659 2/1971 Anthony ..226/l80 Adamov, Czechoslovakia[22] Filed: Aug. 11, 1970 Primary Examiner-Richard A. Schacher [211 ppNo 62,980 Attorney-Richard Low and Murray Schaffer [5 7] ABSTRACT [30]Foreign Apphcauon p Apparatus for mounting distributor and dampeningrollers in Aug. 22, 1969 Czechoslovakia ..5788-69 an offset printingmachine. The distributor roller'is journaled in a bearing secured infixed bushing and the dampening roller [52] US. Cl .226] 180, 226/ l8lis mounted on an arm extending from a body surrounding the [51] lnt.bushing The body is provided with key means permitting ad- Field ofSearc 6/176, 177, 180, l28glll8s7l, justable rotative positioning aboutthe bushing.

10,Claims, 2 Drawing Figures PATENTEBAPR 18 I972 I 3,656,677

We; sTEP/M/EK a INVENTORS BY Z1 8% JOSEF ZELINKA OFFSET PRINTINGMACHINES BACKGROUND OF INVENTION The present invention relates to offsetprinting machines and in particular to apparatus for resilientlymounting paired rollers such as the dampening and distributor rollers ofsuch machines.

Paired rollers, such as the dampening and distributor rollers aregenerally required to be mounted in a manner which allows the pressurebetween them to be regulated. Conventionally means for urging rollerstogether include springs, eccentric bushings, set levers or othercomplex mechanisms. Such techniques are disadvantageous because they arenot readily accessible for adjustment or modification during operation,and tend to prevent access to the other operating mechanism of themachine. A further drawback is that such devices are not capable ofbeing precisely and sensitively adjusted to the exact pressure desired.Above all such devices, particularly the eccentric bushings are complexand expensrve.

.It is an object of the present invention to provide a simple andinexpensive mounting for paired rollers.

It is another object of the present invention to provide an improvedassembly for rollers, such as the distributor and dampening rollers, inoffset printing machines.

It is another object to provide an offset printing machine withapparatus for easily controllingthe pressure between paired cooperativerollers.

It is a specific object of the present invention to provide an improvedapparatus for adjustably mounting the -dampening and distributor rollersof an offset printing machine.

Those objects and others as well as numerous advantages are obtained bythe present invention, as will be seen from the following disclosure.

SUMMARY OF INVENTION In accordance with the present invention apparatusfor mounting paired rollers, such as the dampening rollers, of offsetprinting machines is provided having a support, a bushing fixed in thesupport and a roller rotatably joumaled in the bushing and a holder isrotatably positioned over the bushing. The holder is provided with anarm supporting the other roller and key means located opposite to thearm to position the arm about the bushing. The key means extends withina slot transversely to the axis of the rollers so as to beslidablerelative to the bushing. The key has an inclined face engagingthe surface of the bushing positioning it whereby its interactions withthe bushing causes the holder to rotate about the bushing into a fixedposition.

In the preferred form the arm holding the second roller is eccentric tothe diametric axis of the bushing, whereby gravity causes the arm tofall, moving the second roller into contact with the first roller.Spring means are also provided for resiliently urging the key intoengagement with bushing. The key is provided with variable screw meansaccessible from without the frame to permit its simple adjustment.

F ull details of the present invention are set forth in the followingdescription and the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS In the description reference is made tothe accompanying drawings in which: 7

FIG. 1 is a fragmentary elevational view, partially sectioned along line1-1 of FIG. 2 of the dampening and distributor roller mounting assemblyin accordance with the present invention; and

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.

The drawings show as much of a conventional offset printing press suchas the type illustrated and discribed in Photo- Offset Fundamentals" byJohn E. Gogoli (McKnight and McKnight Publishing Co., Bloomington, 111.,I960, pages 158 et seq.) and commercially available as the ATP ChiefPress, as is needed for a full understanding of this invention.

The actual printing mechanisms, implements, and the plural dampeningmechanisms as well as the paper feeding and delivery devices have beenomitted since they are not directly relevant to the present invention.

The present drawings further illustrate only one end of the assembly ofdistributor and dampening rollers. It is understood that each of therollers are mounted at each of their ends to the spaced frames orsupports of the machine. The mountings at both ends may, and are in factpreferably the same in order to maintain symmeu'y of design function andstress forces although they may however be different if desired.Therefore it is only necessary to show the mounting apparatus at one endof the device since by mirror image reproduction the opposite mountingcan be easily visualized.

Still further, the concept of the present invention may be applied tothe mounting of other paired engaging rollers and the fact that thedrawings and description disclose the mounting of dampening anddistributor rollers should not be taken as limiting in any way.

DESCRIPTION Turning now to FIG. 1 there is seen a paired assembly ofrollers comprising a distributor roller 10 and a dampening roller 10.The dampening roller 10 is of conventional construction having a neckeddown shaft end 13 rotatably joumaled within a bearing 14, and axiallysecured by a C-clamp or retaining washer 16. The bearing 14, ofconventional ball or roller hearing construction, is secured within abore 18 of a bushing 20 which is itself fixedly mounted within theexisting wall or frame support 22 of the offset printing machine. Thebushing 20 is T-shaped, in longitudinal cross section, having a head 24at its outer end and a cylindrical stem 26 extending inwardly andspacedly surrounding the shaft end 13.

Mounted to swing about the bushing 20 is a dampening roller holder,generally depicted by the numeral 28. The holder 28 comprises (FIG. 2) abody 30 in which is formed a bell shaped cavity 32 having straight sidewalls 34, spaced apart substantially equal to the diameter of thebushing stern an angleto the distributor roller 10 so that gravity willnormally cause it and the body to rotate toward the distributor roller10, to maintain the dampening roller 12 in contact with the distributorroller 10. The extent of the bias determines the pressure the dampeningroller exerts on the distributor roller. The. holder 28 is preventedfrom movement axially by a retaining washer 50 and fastener 52, such asa C-clamp, urging the holder body 30 against the head 24 of the bushing20.

The body 30 of the holder 28 is provided with a cylindrical slot or keyway 54 extending through the boss 40 transversely to and beneath thecylindrical stem 26 of the bushing. Located within the transverse keyway 54 is a generally cylindrical feather key 56 having an inclined orsloping upper flat surface 58 adapted to face and engage the bushingstem 26 and a terminal upwardly sloping gib head 60. The sliding key 56is adjustably secured with the key way bore 54 by a headed screw 62having a threaded inner end 64 and engaging within a mating threadedhole 66 in the feather key. The screw 62 has a revolving cylindricalretaining ferrule 68 about which a compression spring 70 is located. Thecompression spring 70 is urged against the boss 40 and the head of thescrew 62 to maintain the screw in proper axial tension. The screw 62 isprevented from axial movement by a bar 72 which fits with a circulargroove 74 cut within the exterior of the screw ferrule 68. The bar 72 issecured to the body boss 42 by a suitable screw fastener 76. Thus byrotating the screw 62 the slide key can be reciprocated within the bore54 so that its inclined surtimely extraction of the key 54.

Because the bushing is fixed against rotation in the wall of framesupport, the adjustment of the feather key causes the holder 28 torotate about the bushing 26. The upper boss 40 of the body is providedwith still another bore 78, diametrically opposedto the key 54, in whichis mounted a sliding contact member 80 and compression spring 82constantly urgingthe contact into engagement with the top of the bushingso as to exert a'bias on the key 54.

- 7 .As a result of this construction the interaction, of the featherkey and the adjustment of its inclined surface, the resilient slidingcontactat the upper boss, and the effect of gravity on the eccentricarmcauses the holder 28 to be urged in an accurate direction biasing orpressing-the dampening roller 12 against the surface of the distributorrollerl0.

In operation, variable adjustment .of the pressure between tion of thefeather key 56. Asthe key changes its position the holder 28 is rotated,swinging the dampening roller. 12, held by the arm 42 into more or lesscompression against the surface of the distributor roller.'Thecompression spring and contact member are counter biasing means servingto maintain the holder secure and vibration free. The gib head 60prevents unlt will then be seen that a simple mechanism is provided bywhich the pressure between dampening and distributor rollers can beeffectivly varied. The present mechanism is free of any complicated cam,eccentric bushing or heavyspring biasing means and adjustment can bemade freely and easily by rotathe rollers is obtained by turning thescrew 62 to shiftthe posi- 4 having an armextending therefrom in whichthe other of said rollers is secured, 1 a feather key located withinsaid holder opposite said arm, and transverse to the axis of saidbushing, said key having an inclined face adapted to engage the surfaceof said bushingand I means for adjusting the. position of said keywithin said holder to cause said holder to be rotatably adjustable aboutsaid bushing in response to the relative of I I the inclined surface ofthe key the surface of the bushing. 2. The apparatus according to claim1 wherein the arm ex.-

tends eccentn'cally from the holder, toward said one roller to urge saidother roller in contact therewith by gravity.

3. The apparatus according to claim 1 including spring means forresiliently biasing said key against said bushing.

'4. The apparatus according to claim 3 wherein said spring meansincludes a compression spring and a slidable eontact member located in abore opposite to said key to thereby exert a bias on said bushingdiametrically opposed to said key.

5. The apparatus according to claim 4 wherein said key is provided withagib head at one end to limit axial movement thereof relative to saidbushin 6. The apparatus according to'claim 3 wherein the means I foradjusting said key comprises a screw having an end extending axiallywithin said key, a revolving retaining ferrule fixedly secured to saidholder and a head extending outwardly of said tion of a singlescrew,which is readily available without the dismantling or removing any partof the roller mechanism or machine. The degree of pressure may bereadily set at any desired sensitivity levels and maintained threatduring operation.

, Various changes and modifications maybe made particular withoutdeparting from the present inventive concept. In particular the shape ofthe holder, body and dampening roller carrying arms may be readiblychanged. The type of key and screw adjustment means may be modified ascan other minor details. It is therefore intended that the presentdisclosures be illustrative only of the present invention and notlimiting thereof.

What is claimed: 1. Apparatus for resiliently mounting a pair ofengaging rollers in an offset printing machine comprising a support, v abushing fixedly secured within said said support, one of said rollersbeing rotatably joumaled within said bushing, a holder rotatably mountedabout said bushing said holder holder whereby rotation of said headcauses movement of said key relative to said holder.

7. The apparatus according to claim 5 wherein said screw is providedwith a compression spring about said ferrule for maintaining said screwheat biased with respect-to said holder.

8. The apparatus accordingtoclaim 1 wherein said holder includes a bodyhaving an internal cavity for receiving said bushing, said cavity havingparallel side walls spaced a distance substantially equally to thediameter of said bushing, an arcuate top wall and anopen bottom, spacedapart a distance substantially greater than the diameter, of saidbushing, a slot formed in said body transverse to said bushing adjacentsaid key being received in said slot, and resilient means 1 is T-shapedhaving its head located outwardly of said support and a cylindrical stemextending through said support to surround the axle of said roller, andmeansfor axially securing said'holder body on said bushing, saidsecuring means urging said body against the inner face of said supportand said bushing against the outer face of said support.

10. A distributor and dampening roller assembly for an offset printingmachine according to claim 1, wherein said rollers have extending axlesat each end.'

1. Apparatus for resiliently mounting a pair of engaging rollers in anoffset printing machine comprising a support, a bushing fixedly securedwithin said said support, one of said rollers being rotatably journaledwithin said bushing, a holder rotatably mounted about said bushing saidholder having an arm extending therefrom in which the other of saidrollers is secured, a feather key located within said holder oppositesaid arm, and transverse to the axis of said bushing, said key having aninclined face adapted to engage the surface of said bushing and meansfor adjusting the position of said key within said holder To cause saidholder to be rotatably adjustable about said bushing in response to therelative position of the inclined surface of the key the surface of thebushing.
 2. The apparatus according to claim 1 wherein the arm extendseccentrically from the holder, toward said one roller to urge said otherroller in contact therewith by gravity.
 3. The apparatus according toclaim 1 including spring means for resiliently biasing said key againstsaid bushing.
 4. The apparatus according to claim 3 wherein said springmeans includes a compression spring and a slidable contact memberlocated in a bore opposite to said key to thereby exert a bias on saidbushing diametrically opposed to said key.
 5. The apparatus according toclaim 4 wherein said key is provided with a gib head at one end to limitaxial movement thereof relative to said bushing.
 6. The apparatusaccording to claim 3 wherein the means for adjusting said key comprisesa screw having an end extending axially within said key, a revolvingretaining ferrule fixedly secured to said holder and a head extendingoutwardly of said holder whereby rotation of said head causes movementof said key relative to said holder.
 7. The apparatus according to claim5 wherein said screw is provided with a compression spring about saidferrule for maintaining said screw head biased with respect to saidholder.
 8. The apparatus according to claim 1 wherein said holderincludes a body having an internal cavity for receiving said bushing,said cavity having parallel side walls spaced a distance substantiallyequally to the diameter of said bushing, an arcuate top wall and an openbottom, spaced apart a distance substantially greater than the diameterof said bushing, a slot formed in said body transverse to said bushingadjacent said key being received in said slot, and resilient meansextending from said arcuate top normal to said bushing to urge said bodyupwardly whereby said key engages said bushing.
 9. The apparatusaccording to claim 8 wherein said bushing is T-shaped having its headlocated outwardly of said support and a cylindrical stem extendingthrough said support to surround the axle of said roller, and means foraxially securing said holder body on said bushing, said securing meansurging said body against the inner face of said support and said bushingagainst the outer face of said support.
 10. A distributor and dampeningroller assembly for an offset printing machine according to claim 1,wherein said rollers have extending axles at each end.